El lector prefiere estudiar español en la biblioteca tranquila.

Lector literally means reader (someone who reads).

• El lector = the (male) reader
• La lectora = the (female) reader

In this sentence, the subject is specifically “the reader,” not just any person or any student.

Could you use other words? Yes, depending on what you want to emphasize:

• El estudiante = the (male) student
• La estudiante = the (female) student
• La persona = the person (gender-neutral, grammatically feminine)

So the choice of lector is about meaning and context. Grammatically, it’s just a regular masculine noun with its article el.

Preferir is a verb that means to prefer.

• El lector prefiere… = The reader prefers…

You don’t need a after preferir when you follow it directly with a verb in the infinitive (like estudiar):

• prefiere estudiar = prefers to study

You would use a if you’re comparing two things explicitly:

• El lector prefiere estudiar en la biblioteca tranquila a estudiar en casa.
  The reader prefers to study in the quiet library to (rather than) studying at home.

But in the original sentence, we aren’t contrasting two options; we’re just saying what he prefers to do, so prefiere estudiar is enough.

After verbs of desire, preference, or intention (like querer, preferir, necesitar, poder, deber), Spanish usually uses the infinitive when the subject is the same person.

So:

• El lector prefiere estudiar… = The reader prefers to study…

You cannot say prefiere estudia. That’s mixing conjugated forms incorrectly.

Compare:

• Yo quiero estudiar. = I want to study.
• Él prefiere leer. = He prefers to read.

If the subject changes, you use a clause with que and a conjugated verb:

• El lector prefiere que otros estudien en voz baja.
  The reader prefers that others study quietly.

Both are possible, but they have slightly different usage patterns.

1. Without article (very common when saying you study/speak languages):

   • Estudiar español = to study Spanish (the language in general)
   • Hablar español = to speak Spanish

2. With article (el español) often refers to the language more as a concept or subject, and can sound a bit more formal or specific in some contexts:

   • Estudiar el español del siglo XIX. = to study 19th-century Spanish.
   • El español es una lengua muy extendida. = Spanish is a very widespread language.

In everyday speech, when talking about learning or speaking a language, native speakers often omit the article, especially in Latin America:

• Quiero aprender español.
• Ella enseña inglés.

So estudiar español is perfectly natural and idiomatic.

The preposition depends on the idea being expressed:

• en = in, at, inside (location)
• a = to (movement or direction)

In this sentence:

• …estudiar español en la biblioteca…
  = to study Spanish in/at the library (location)

If you talk about going to the library, you use a:

• El lector va a la biblioteca para estudiar.
  The reader goes to the library to study.

So:

• estar / estudiar / leer / trabajar en la biblioteca
• ir / venir / caminar a la biblioteca

In Spanish, adjectives usually go after the noun:

• la biblioteca tranquila = the quiet library

This is the neutral, most common order: noun + adjective.

You can put many adjectives before the noun, but that often adds a nuance (more subjective, emotional, literary, or emphasizing a quality you already assume):

• la tranquila biblioteca
  Can sound a bit more poetic or expressive, like “the peaceful library” as a known, characteristic quality.

For a straightforward description, especially at beginner/intermediate levels, stick with:

• noun + adjective: la biblioteca tranquila

Adjectives in Spanish must agree in gender and number with the noun they describe.

• biblioteca is a feminine singular noun (ends in -a, and its article is la).
• So the adjective must also be feminine singular: tranquila.

Agreement pattern:

• el lugar tranquilo (masculine singular)
• los lugares tranquilos (masculine plural)
• la biblioteca tranquila (feminine singular)
• las bibliotecas tranquilas (feminine plural)

Using tranquilo with biblioteca would be grammatically incorrect:
✗ la biblioteca tranquilo

It’s not wrong, but it slightly changes the feel.

• El lector prefiere estudiar español…
  Very natural, neutral, what you’re most likely to say in conversation.

• El lector prefiere estudiar el español…
  Sounds a bit more formal or specific, as if talking about Spanish as a particular school subject, or about a specific variety or aspect of Spanish.

In everyday Latin American usage, especially for “to study Spanish” in general, without the article is more common:

• Voy a estudiar español en la universidad.

• Estudiar = to study (to apply yourself, to do exercises, to read, etc.)
• Aprender = to learn (to actually acquire knowledge/skills)

In this sentence:

• prefiere estudiar español
  = he likes doing the activity of studying Spanish (reading, doing homework, etc.) in the library.

If you say:

• prefiere aprender español en la biblioteca

…it sounds more like “he prefers learning Spanish in the library” (maybe he learns better there). It’s possible, but the typical collocation when talking about what you do in a library is estudiar.

Spanish word order with verbs plus infinitives is usually:

• conjugated verb + infinitive + object

So:

• prefiere estudiar español
  = prefers to study Spanish

Putting español before estudiar (prefiere español estudiar) sounds ungrammatical and very foreign. Think:

• prefiere leer libros (not prefiere libros leer)
• quiere comer pizza (not quiere pizza comer)

Correct patterns:

• Sujeto + verbo conjugado + infinitivo + complemento
  
  • El lector prefiere estudiar español en la biblioteca tranquila.

The infinitive is preferir (to prefer). It’s a stem-changing -ir verb: e → ie in some forms.

Present tense of preferir:

• yo prefiero
• tú prefieres
• él / ella / usted prefiere
• nosotros / nosotras preferimos (no stem change)
• vosotros / vosotras preferís (Spain; no stem change)
• ellos / ellas / ustedes prefieren

In the sentence:

• El lector prefiere…
  = 3rd person singular: él prefiere

In Spanish, names of languages and nationalities are not capitalized, unless they start a sentence:

• Hablo español, inglés y francés.
• Soy mexicano.
• El español es una lengua romance. (capital only because it’s the first word)

So español is written with a lowercase e in the middle of a sentence.

Yes, but only if the subject is already clear from context.

Spanish often omits subject pronouns (yo, tú, él, etc.) because the verb ending shows who the subject is. But with a noun subject like el lector, you usually keep it unless:

• it was mentioned just before and is clearly the same:
  
  • El lector entra. Prefiere estudiar español en la biblioteca tranquila.

In isolation, if you just say:

• Prefiere estudiar español en la biblioteca tranquila.

…it means “He/She prefers to study Spanish in the quiet library,” but we don’t know who “he/she” is. So including El lector makes it explicit.

A couple of tips:

• español:

  • ñ is a separate letter, pronounced like the ny in “canyon”: es-pa-nyol.
  • Stress is on the last syllable: es-pa-ñol.

• biblioteca:

  • Break it as bib-lio-te-ca.
  • The b and v sound the same in most Latin American accents.
  • Stress is on te: bib-lio-TE-ca.

• tranquila:

  • The qu before i is like k in English: tran-KEE-la (but shorter).
  • Stress is on qui: tran-QUI-la.

These pronunciations are the same across Latin America, with only small accent differences.